A ring with liquid crystals that claimed to reveal your emotions through color — pure 1970s pseudoscience that briefly became a genuine sales phenomenon.
Mood Ring was a genuine nationwide craze decades before "going viral" was a phrase — and it's still made and sold today. This is a genuine pre-internet product — a real, nationwide sales phenomenon decades before social media existed, spread by nothing but word of mouth, in-store demonstration, and traditional advertising. Many of these are still in production today, largely unchanged.
Launched in early 1975, mood rings weren't patented, so competing jewelers flooded the market almost immediately — which fueled the craze but also caused it to collapse just as fast once the market oversaturated by that December.